A retaining wall is a structure erected to support a road slope and an excavated or filled embankment in order to prevent collapse of the road slope and the embankment due to the earth pressure. Generally, the lateral displacement is prevented by filling-up a space between the retaining wall and the road slope or the embankment with the back-filler containing fiber reinforcement having high tension and friction, i.e., geo-grid. That is, the retaining wall assures the stability of diversity structures such as road slopes and the embankments. Therefore, various retaining wall structures and methods of building thereof were introduced. For example, interlocking blocks were used to build a retaining wall that supports the earth pressure of a soil structure. Also, sand sacks or soil sacks were used instead of using the interlocking blocks.
When the sand sacks or the soil sacks are used to build the retaining wall, the retaining wall is built without fixing those sacks each others and their positions in the retaining wall are maintained only by their gravity. Therefore, if the back-filler portion of the retaining wall is sunken after building the retaining wall with those sacks, the vertical shape of the retaining wall is easily deformed by the horizontal shearing force arisen between the retaining walls. As a result, the reinforcement, i.e., geo-grid, in the back-filler is destroyed. Therefore, the retaining wall according to the related art has highly limited conditions of the height and the slop, and the durability thereof is low.